The Cell Culture Core, designated as Core B, is a centralized facility that provides primary alveolar epithelial type 2 and type 1 cells from rats and mice to each of the four projects and to Core C. Additionally, the Core provides primary derived fibroblasts and maintains secondary alveolar epithelial cell lines for the PPG. Centralization of the cell culture facilities will ensure that a continuous supply of high quality alveolar epithelial cells is available to each of the four projects. The cell culture facility personnel has extensive experience in the isolation of primary alveolar type 2 and type 1 cells from rats and mice, as well as general cell culture techniques. The consolidation of the cell culture facilities will provide an economical means of isolating and culturing alveolar epithelial cells. This translates into reduced overall costs (i.e. personnel, reagents, animals) and more importantly maintains the precision and accuracy with which the cells are isolated and cultured